Attosecond cascades and time delays in one-electron photoionization

Sukiasyan, Suren; Ishikawa, Kenichi L.; Ivanov, Misha

doi:10.1103/physreva.86.033423

Cited by 29 publications

(36 citation statements)

References 33 publications

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“…The operator h is the one-electron part of the total Hamiltonian, and J is the Coulomb operator defined in Eq. (12). The TD-RHF method cannot describe the spatially different motions of the ionizing electron and that left in the ionic core, since it enforces the closed-shell structure.…”

Section: Theoretical Analyses Of the Two Electron Wavefunctionmentioning

confidence: 99%

The structure of approximate two electron wavefunctions in intense laser driven ionization dynamics

Sato¹,

Ishikawa²

2014

J. Phys. B: At. Mol. Opt. Phys.

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The structure of approximate two electron wavefunction is deeply investigated, both theoretically and numerically, in the strong-field driven ionization dynamics. Theoretical analyses clarify that for two electron singlet systems, the previously proposed time-dependent extended Hartree-Fock (TD-EHF) method [Phys. Rev. A 51, 3999 (1995)] is equivalent to the multiconfiguration time-dependent Hartree-Fock method with two occupied orbitals. The latter wavefunction is further transformed into the natural expansion form, enabling the direct propagation of the natural orbitals (NOs). These methods, as well as the conventional time-dependent Hartree-Fock (TDHF) method, are numerically assessed for the description of ionization dynamics of one-dimensional helium atom model. This numerical analysis (i) explains the reason behind the well-known failure of TDHF method to describe tunneling ionization, (ii) demonstrates the interpretive power of the TD-EHF wavefunction both in the original nonorthogonal and the NO-based formulations, and (iii) highlights different manifestations of the electron correlation (effect beyond the single determinant description), in tunneling ionization, high harmonic generation, and nonsequential double ionization. Possible extensions of the NO basis approach to multielectron systems are briefly discussed.

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Section: Theoretical Analyses Of the Two Electron Wavefunctionmentioning

confidence: 99%

The structure of approximate two electron wavefunctions in intense laser driven ionization dynamics

Sato¹,

Ishikawa²

2014

J. Phys. B: At. Mol. Opt. Phys.

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“…Alternatively, the timing of the photoionization process can also be monitored by inspecting the timedependent norm of the ionized portion of the electronic wavepacket in the continuum (Kheifets and Ivanov, 2010;Sukiasyan et al, 2012) given by the expectation value [Eq. (2.18)…”

Section: Example: Photodetachment From a Model Atommentioning

confidence: 99%

Attosecond chronoscopy of photoemission

2015

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Recent advances in the generation of well characterized sub-femtosecond laser pulses have opened up unpredicted opportunities for the real-time observation of ultrafast electronic dynamics in matter. Such attosecond chronoscopy allows a novel look at a wide range of fundamental photophysical and photochemical processes in the time domain, including Auger and autoionization processes, photoemission from atoms, molecules, and surfaces, complementing conventional energy-domain spectroscopy. Attosecond chronoscopy raises fundamental conceptual and theoretical questions as which novel information becomes accessible and which dynamical processes can be controlled and steered. These questions are currently a matter of lively debate which we address in this review. We will focus on one prototypical case, the chronoscopy of the photoelectric effect by attosecond streaking. Is photoionization instantaneous or is there a finite response time of the electronic wavefunction to the photoabsorption event? Answers to this question turn out to be far more complex and multi-faceted than initially thought. They touch upon fundamental issues of time and time delay as observables in quantum theory. We review recent progress of our understanding of time-resolved photoemission from atoms, molecules, and solids. We will highlight the unresolved and open questions and we point to future directions aiming at the observation and control of electronic motion in more complex nanoscale structures and in condensed matter.

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“…While direct solution of the time-dependent Schrödinger equation (TDSE) provides exact description, this method is virtually unfeasible for multielectron systems beyond He [17][18][19][20][21][22][23][24][25][26][27][28][29] and H 2 [30][31][32]. As a result, single-active electron (SAE) approximation is widely used, in which only the outermost electron is explicitly treated, and the effect of the others, assumed to be frozen, is embedded in a model potential.…”

mentioning

confidence: 99%

Time-dependent complete-active-space self-consistent-field method for multielectron dynamics in intense laser fields

2013

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The time-dependent complete-active-space self-consistent-field (TD-CASSCF) method for the description of multielectron dynamics in intense laser fields is presented, and a comprehensive description of the method is given. It introduces the concept of frozen-core (to model tightly bound electrons with no response to the field), dynamical-core (to model electrons tightly bound but responding to the field), and active (fully correlated to describe ionizing electrons) orbital subspaces, allowing compact yet accurate representation of ionization dynamics in many-electron systems. The classification into the subspaces can be done flexibly, according to simulated physical situations and desired accuracy, and the multiconfiguration time-dependent Hartree-Fock (MCTDHF) approach is included as a special case. To assess its performance, we apply the TD-CASSCF method to the ionization dynamics of one-dimensional lithium hydride (LiH) and LiH dimer models, and confirm that the present method closely reproduces rigorous MCTDHF results if active orbital space is chosen large enough to include appreciably ionizing electrons. The TD-CASSCF method will open a way to the first-principle theoretical study of intense-field induced ultrafast phenomena in realistic atoms and molecules.PACS numbers: 32.80. Rm, 42.65.Ky

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Attosecond cascades and time delays in one-electron photoionization

Cited by 29 publications

References 33 publications

The structure of approximate two electron wavefunctions in intense laser driven ionization dynamics

The structure of approximate two electron wavefunctions in intense laser driven ionization dynamics

Attosecond chronoscopy of photoemission

Time-dependent complete-active-space self-consistent-field method for multielectron dynamics in intense laser fields

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